Advancements in Pharmaceutical Wastewater Pretreatment Technologies
Pharmaceutical wastewater pretreatment
With the rapid development of social and economic, in recent years the pharmaceutical industry has continued to grow and has made significant achievements, but the resulting pharmaceutical industrial wastewater has become a huge problem plaguing enterprises and the government. The pharmaceutical industry is mainly based on the chemical synthesis of pharmaceuticals, biopharmaceuticals, and traditional Chinese medicine-based pharmaceuticals, production has a variety of products and complex processes, and the production scale varies. Chemical pharmaceutical wastewater can be roughly divided into four categories, the production process of waste liquid, mother liquor, etc.; recovery of residual liquid including solvents, premise liquid, by-products, etc.; auxiliary process drainage, such as cooling water, etc.; equipment and the ground, such as rinsing wastewater; domestic sewage.
Pharmaceutical wastewater is mainly characterized by the unstable proportion of water quality components, complex composition, high concentration of toxic and hazardous pollutants, high chromaticity, poor biochemistry, and high content of difficult to degrade, in addition to the water quality and quantity is also very unstable. Therefore, how to treat pharmaceutical wastewater to meet the requirements of the "Comprehensive Emission Standards for Sewage" is the dual goal of environmental protection and enterprise efficiency.
Wastewater technology
Different pharmaceutical companies due to raw materials, processes, wastewater volume, and the degree of treatment are different, and the choice of treatment methods are not the same. According to the principle of each method, it is generally summarized as a physical method, chemical method, and biological method. In the process of pharmaceutical wastewater treatment, biological treatment of wastewater can not be directly discharged, usually the first physical method, chemical pre-treatment to improve its biochemical properties, reduce toxicity, and then continue to biological treatment, wastewater in order to meet the discharge requirements.
Pharmaceutical wastewater pretreatment solutions
Pharmaceutical wastewater for high COD, high nitrogen and phosphorus, high salinity, deep chromaticity, complex composition and poor biochemistry, and other characteristics, which often involves micro electrolysis Fenton system for pre-treatment, through the degradation of macromolecular organic matter and destruction, so as to achieve a reduction in its toxicity and improve the biochemistry of the purpose, and then united with the other wastewater treatment process, wastewater will be treated to the sewage treatment plant in the region to meet the standard requirements and discharged into the local sewage treatment plant, and subsequently by the sewage treatment plant to meet the discharge requirements, and then continued by the biological method. Local sewage treatment plant, followed by sewage treatment plant for further treatment.
1. Microelectrolysis reaction
The reaction mechanism of iron and carbon microelectrolysis is that when the iron and carbon filler is submerged in acidic wastewater, countless microcells will be formed in the wastewater due to the electrode potential difference between iron and carbon (0.9-17V). These micro-cells are low-potential iron as the anode, and high-potential carbon as the cathode, in the aqueous solution containing acidic electrolyte electrochemical reaction. The reaction process produces a large number of primitive Fe2+ and new ecological [-H], which have very high chemical activity and can change the structure and characteristics of many organic substances in wastewater so that the organic matter breaks the chain, opens the ring, and other effects. Improve the biochemistry of wastewater. The cathode generates OH during the reaction process, which improves the PH value of treated wastewater.
2. Fenton reaction
After the wastewater has been treated by the previous iron carbon microelectrolysis, part of the organic pollutants have been oxidized and removed, and the structure of the remaining part of the organic matter has been changed, which is conducive to further oxidation treatment. Combined with the experience of treatment of such wastewater, wastewater can be removed by adding a certain amount of hydrogen peroxide and ferrous and catalyst ions in water to form a free radical strong oxidizer, which can remove the vast majority of organic matter in wastewater.
3. Neutralization and precipitation
By adjusting the pH value of the acidic effluent of the microelectrolysis Fenton system to about 8, and at the same time adding coagulants to achieve the removal of suspended solids and other precipitates in wastewater. When treating chemical wastewater, the neutralization and precipitation process can independently remove pollutants in the wastewater and can also be used as an intermediate project to improve the effect of wastewater treatment.
